1. Field of the Invention
This invention relates in general to subsea wellhead housings and wellhead connectors, and in particular to a seal assembly that will provide sealing if the wellhead housing conical sealing surface becomes damaged.
2. Description of the Prior Art
A subsea well of the type concerned herein has a wellhead housing located at the subsea floor. The wellhead housing is a tubular member having a bore. A wellhead connector will be lowered from a vessel at the surface over the wellhead housing to connect the subsea well to the surface. The wellhead connector has connection means for connecting to the exterior of the wellhead housing.
The wellhead housing has an upward facing shoulder on its upper end that is engaged by a downward facing shoulder on the lower end of the wellhead connector. The wellhead housing has a conical upward facing shoulder at its upper end. The wellhead connector has a conical downward facing shoulder. The wellhead connector also has a recess located radially inward from the downward facing shoulder.
A metal seal locates between the wellhead connector and the wellhead housing. The metal seal has a conical upper surface that seals against the conical surface of the wellhead connector. The metal seal has a lower conical surface that seals against the conical surface of the wellhead housing. A rib extends radially outward from the two conical surfaces for location in the recess.
While the metal seal works well, if the conical surface of the wellhead housing becomes damaged, problems will occur. The metal seal will not seal against the damaged lower surface. The wellhead housing is cemented in the ground and connected to casing and conductor pipe. It is not possible to pull the wellhead housing from the subsea floor for redressing the conical sealing surface.